Structural characterization of polysaccharides from Dictyophora rubrovolvata mycelium and their immunostimulatory activity in RAW264.7 cells

In this study, a homogeneous polysaccharide, named, DRMP-1 was isolated from the mycelium of Dictyophora rubrovolvata by water extraction and alcohol precipitation, and its structure and activity were studied. The molecular weight of DRMP-1 is 2.33 x 106 Da, and it does not contain protein and nucleic acid. DRMP-1 is composed of mannose, glucose and galactose with a molar ratio of 0.04: 1: 0.04. Through methylation and NMR analysis, DRMP-1 is mainly composed of 1 -> 6)-alpha-Galp-( 1 ->, T-alpha-D-Glcp, -> 1)-alpha-D-Manp, -> 6)-beta-D-Glcp-( 1 ->, -> 4, 6)- alpha-D-Manp-( 1 ->, -> 4)- alpha-D-Glcp-( 1 ->, -> 3)-beta-D-Glcp-( 1 -> and -> 4, 6)- alpha-D-Glcp-( 1 ->. In addition, the immunomodulative activity of DRMP-1 was evaluated by establishing the RAW264.7 cell model. The results showed that DRMP-1 could significantly increase phagocytosis activity and NO production more than twice as much as that of the blank group, and could increase intracellular ACP, LSZ and SOD activities. Therefore, it is concluded that the polysaccharide of Dictyophora rubrovolvata mycelium may be a potential immunomodulator.